Detroit Tigers: Who ya got between Anibal Sanchez and Shane Greene?
By Matt Snyder
The Detroit Tigers have gotten good results from Shane Greene and poor results from Anibal Sanchez but advanced metrics paint a more complicated picture.
The Detroit Tigers have a bullpen problem. That is not disputed by anyone. Whether you like advanced metrics or traditional ones, the statistics all paint the same picture: They’re 28th in the major leagues in relief pitcher WAR, 20th in FIP and xFIP, and 30th in ERA.
But the question of which relievers are good and which are bad isn’t as easily settled. Take the cases of Shane Greene and Anibal Sanchez. Sanchez has been the epitome of the bullpen struggles this year with 21 runs allowed (16 earned) in 16.2 innings pitched (8.64 ERA). Greene’s results have been on the other end of the spectrum with just two runs allowed in 9.1 innings of work (1.93 ERA).
What’s interesting, however, is that one metric doesn’t see Greene and Sanchez all that differently. Pitching ERA predictor xFIP actually has Sanchez as slightly better — 4.91 to 5.09. A big xFIP believer might expect these two pitchers to perform identically down the stretch.
Both Sanchez and Greene have struck out more than 20% of the batters they’ve faced but Greene has walked a ton of batters while Sanchez has been closer to average in that regard. On the other hand, Sanchez has seen a large percentage of his fly balls leave the yard while Greene has yet to give up a long ball this season.
I (personally) don’t think it would be right to expect Sanchez to out-perform Greene going forward — Statcast data indicates that Greene has been giving up softer contact than Sanchez — but it’s interesting that there’s this one metric that should cause our confidence in the matter to falter just a little bit.
How much do we really know about predicting baseball performance with the eye test, and how much do we insist we know due to confirmation bias and convincing ourselves to see patterns where none really exist? We should always give a bit of credence to the idea of regression to the mean (and that’s what xFIP does to a large degree).
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Don’t like Greene? Replace his 5.09 xFIP with Alex Wilson‘s 5.15 and you could have the same conversation. It’s rare for a pitcher to have success with the low strikeout rate profile that Wilson employs.